Index: head/lib/libmemstat/memstat_malloc.c
===================================================================
--- head/lib/libmemstat/memstat_malloc.c
+++ head/lib/libmemstat/memstat_malloc.c
@@ -317,7 +317,7 @@
 	int hint_dontsearch, j, mp_maxcpus, mp_ncpus, ret;
 	char name[MEMTYPE_MAXNAME];
 	struct malloc_type_stats mts;
-	struct malloc_type_internal mti, *mtip;
+	struct malloc_type_internal *mtip;
 	struct malloc_type type, *typep;
 	kvm_t *kvm;
 
@@ -372,18 +372,17 @@
 			list->mtl_error = ret;
 			return (-1);
 		}
+		if (type.ks_version != M_VERSION) {
+			warnx("type %s with unsupported version %lu; skipped",
+			    name, type.ks_version);
+			continue;
+		}
 
 		/*
 		 * Since our compile-time value for MAXCPU may differ from the
 		 * kernel's, we populate our own array.
 		 */
-		mtip = type.ks_handle;
-		ret = kread(kvm, mtip, &mti, sizeof(mti), 0);
-		if (ret != 0) {
-			_memstat_mtl_empty(list);
-			list->mtl_error = ret;
-			return (-1);
-		}
+		mtip = &type.ks_mti;
 
 		if (hint_dontsearch == 0) {
 			mtp = memstat_mtl_find(list, ALLOCATOR_MALLOC, name);
@@ -404,7 +403,7 @@
 		 */
 		_memstat_mt_reset_stats(mtp, mp_maxcpus);
 		for (j = 0; j < mp_ncpus; j++) {
-			ret = kread_zpcpu(kvm, (u_long)mti.mti_stats, &mts,
+			ret = kread_zpcpu(kvm, (u_long)mtip->mti_stats, &mts,
 			    sizeof(mts), j);
 			if (ret != 0) {
 				_memstat_mtl_empty(list);
Index: head/sys/cddl/dev/dtmalloc/dtmalloc.c
===================================================================
--- head/sys/cddl/dev/dtmalloc/dtmalloc.c
+++ head/sys/cddl/dev/dtmalloc/dtmalloc.c
@@ -114,7 +114,7 @@
 dtmalloc_type_cb(struct malloc_type *mtp, void *arg __unused)
 {
 	char name[DTRACE_FUNCNAMELEN];
-	struct malloc_type_internal *mtip = mtp->ks_handle;
+	struct malloc_type_internal *mtip = &mtp->ks_mti;
 	int i;
 
 	/*
Index: head/sys/kern/kern_malloc.c
===================================================================
--- head/sys/kern/kern_malloc.c
+++ head/sys/kern/kern_malloc.c
@@ -175,14 +175,8 @@
 };
 
 /*
- * Zone to allocate malloc type descriptions from.  For ABI reasons, memory
- * types are described by a data structure passed by the declaring code, but
- * the malloc(9) implementation has its own data structure describing the
- * type and statistics.  This permits the malloc(9)-internal data structures
- * to be modified without breaking binary-compiled kernel modules that
- * declare malloc types.
+ * Zone to allocate per-CPU storage for statistics.
  */
-static uma_zone_t mt_zone;
 static uma_zone_t mt_stats_zone;
 
 u_long vm_kmem_size;
@@ -342,7 +336,7 @@
 	size_t len;
 	u_int val;
 
-	mtip = mtp->ks_handle;
+	mtip = &mtp->ks_mti;
 	desc = mtp->ks_shortdesc;
 	if (desc == NULL || (len = strlen(desc)) == 0)
 		val = 0;
@@ -356,7 +350,7 @@
 {
 	struct malloc_type_internal *mtip;
 
-	mtip = mtp->ks_handle;
+	mtip = &mtp->ks_mti;
 
 	KASSERT(mtip->mti_zone < numzones,
 	    ("mti_zone %u out of range %d",
@@ -371,7 +365,7 @@
 {
 	struct malloc_type_internal *mtip;
 
-	mtip = mtp->ks_handle;
+	mtip = &mtp->ks_mti;
 	mtip->mti_zone = 0;
 }
 
@@ -404,7 +398,7 @@
 	struct malloc_type_stats *mtsp;
 
 	critical_enter();
-	mtip = mtp->ks_handle;
+	mtip = &mtp->ks_mti;
 	mtsp = zpcpu_get(mtip->mti_stats);
 	if (size > 0) {
 		mtsp->mts_memalloced += size;
@@ -447,7 +441,7 @@
 	struct malloc_type_stats *mtsp;
 
 	critical_enter();
-	mtip = mtp->ks_handle;
+	mtip = &mtp->ks_mti;
 	mtsp = zpcpu_get(mtip->mti_stats);
 	mtsp->mts_memfreed += size;
 	mtsp->mts_numfrees++;
@@ -524,7 +518,7 @@
 #ifdef INVARIANTS
 	int indx;
 
-	KASSERT(mtp->ks_magic == M_MAGIC, ("malloc: bad malloc type magic"));
+	KASSERT(mtp->ks_version == M_VERSION, ("malloc: bad malloc type version"));
 	/*
 	 * Check that exactly one of M_WAITOK or M_NOWAIT is specified.
 	 */
@@ -848,7 +842,7 @@
 	void *addr;
 
 	addr = *addrp;
-	KASSERT(mtp->ks_magic == M_MAGIC, ("free: bad malloc type magic"));
+	KASSERT(mtp->ks_version == M_VERSION, ("free: bad malloc type version"));
 	KASSERT(curthread->td_critnest == 0 || SCHEDULER_STOPPED(),
 	    ("free: called with spinlock or critical section held"));
 
@@ -965,8 +959,8 @@
 	unsigned long alloc;
 	void *newaddr;
 
-	KASSERT(mtp->ks_magic == M_MAGIC,
-	    ("realloc: bad malloc type magic"));
+	KASSERT(mtp->ks_version == M_VERSION,
+	    ("realloc: bad malloc type version"));
 	KASSERT(curthread->td_critnest == 0 || SCHEDULER_STOPPED(),
 	    ("realloc: called with spinlock or critical section held"));
 
@@ -1193,13 +1187,6 @@
 	mt_stats_zone = uma_zcreate("mt_stats_zone",
 	    sizeof(struct malloc_type_stats), NULL, NULL, NULL, NULL,
 	    UMA_ALIGN_PTR, UMA_ZONE_PCPU);
-	mt_zone = uma_zcreate("mt_zone", sizeof(struct malloc_type_internal),
-#ifdef INVARIANTS
-	    mtrash_ctor, mtrash_dtor, mtrash_init, mtrash_fini,
-#else
-	    NULL, NULL, NULL, NULL,
-#endif
-	    UMA_ALIGN_PTR, UMA_ZONE_MALLOC);
 	for (i = 0, indx = 0; kmemzones[indx].kz_size != 0; indx++) {
 		int size = kmemzones[indx].kz_size;
 		const char *name = kmemzones[indx].kz_name;
@@ -1230,12 +1217,12 @@
 	KASSERT(vm_cnt.v_page_count != 0, ("malloc_register before vm_init"));
 
 	mtp = data;
-	if (mtp->ks_magic != M_MAGIC)
-		panic("malloc_init: bad malloc type magic");
+	if (mtp->ks_version != M_VERSION)
+		panic("malloc_init: unsupported malloc type version %lu",
+		    mtp->ks_version);
 
-	mtip = uma_zalloc(mt_zone, M_WAITOK | M_ZERO);
+	mtip = &mtp->ks_mti;
 	mtip->mti_stats = uma_zalloc_pcpu(mt_stats_zone, M_WAITOK | M_ZERO);
-	mtp->ks_handle = mtip;
 	mtp_set_subzone(mtp);
 
 	mtx_lock(&malloc_mtx);
@@ -1251,18 +1238,15 @@
 	struct malloc_type_internal *mtip;
 	struct malloc_type_stats *mtsp;
 	struct malloc_type *mtp, *temp;
-	uma_slab_t slab;
 	long temp_allocs, temp_bytes;
 	int i;
 
 	mtp = data;
-	KASSERT(mtp->ks_magic == M_MAGIC,
-	    ("malloc_uninit: bad malloc type magic"));
-	KASSERT(mtp->ks_handle != NULL, ("malloc_deregister: cookie NULL"));
+	KASSERT(mtp->ks_version == M_VERSION,
+	    ("malloc_uninit: bad malloc type version"));
 
 	mtx_lock(&malloc_mtx);
-	mtip = mtp->ks_handle;
-	mtp->ks_handle = NULL;
+	mtip = &mtp->ks_mti;
 	if (mtp != kmemstatistics) {
 		for (temp = kmemstatistics; temp != NULL;
 		    temp = temp->ks_next) {
@@ -1295,9 +1279,7 @@
 		    temp_allocs, temp_bytes);
 	}
 
-	slab = vtoslab((vm_offset_t) mtip & (~UMA_SLAB_MASK));
 	uma_zfree_pcpu(mt_stats_zone, mtip->mti_stats);
-	uma_zfree_arg(mt_zone, mtip, slab);
 }
 
 struct malloc_type *
@@ -1346,7 +1328,7 @@
 	 * Insert alternating sequence of type headers and type statistics.
 	 */
 	for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
-		mtip = (struct malloc_type_internal *)mtp->ks_handle;
+		mtip = &mtp->ks_mti;
 
 		/*
 		 * Insert type header.
@@ -1483,7 +1465,7 @@
 				ties = 1;
 				continue;
 			}
-			size = get_malloc_stats(mtp->ks_handle, &allocs,
+			size = get_malloc_stats(&mtp->ks_mti, &allocs,
 			    &inuse);
 			if (size > cur_size && size < last_size + ties) {
 				cur_size = size;
@@ -1493,7 +1475,7 @@
 		if (cur_mtype == NULL)
 			break;
 
-		size = get_malloc_stats(cur_mtype->ks_handle, &allocs, &inuse);
+		size = get_malloc_stats(&cur_mtype->ks_mti, &allocs, &inuse);
 		db_printf(fmt_entry, cur_mtype->ks_shortdesc, inuse,
 		    howmany(size, 1024), allocs);
 
@@ -1517,17 +1499,17 @@
 		return;
 	}
 	mtp = (void *)addr;
-	if (mtp->ks_magic != M_MAGIC) {
-		db_printf("Magic %lx does not match expected %x\n",
-		    mtp->ks_magic, M_MAGIC);
+	if (mtp->ks_version != M_VERSION) {
+		db_printf("Version %lx does not match expected %x\n",
+		    mtp->ks_version, M_VERSION);
 		return;
 	}
 
-	mtip = mtp->ks_handle;
+	mtip = &mtp->ks_mti;
 	subzone = mtip->mti_zone;
 
 	for (mtp = kmemstatistics; mtp != NULL; mtp = mtp->ks_next) {
-		mtip = mtp->ks_handle;
+		mtip = &mtp->ks_mti;
 		if (mtip->mti_zone != subzone)
 			continue;
 		db_printf("%s\n", mtp->ks_shortdesc);
Index: head/sys/sys/malloc.h
===================================================================
--- head/sys/sys/malloc.h
+++ head/sys/sys/malloc.h
@@ -63,7 +63,7 @@
 #define	M_EXEC		0x4000		/* allocate executable space */
 #define	M_NEXTFIT	0x8000		/* only for vmem, follow cursor */
 
-#define	M_MAGIC		877983977	/* time when first defined :-) */
+#define	M_VERSION	2020110501
 
 /*
  * Two malloc type structures are present: malloc_type, which is used by a
@@ -104,18 +104,17 @@
 					/* DTrace probe ID array. */
 	u_char		mti_zone;
 	struct malloc_type_stats	*mti_stats;
+	u_long		mti_spare[8];
 };
 
 /*
- * Public data structure describing a malloc type.  Private data is hung off
- * of ks_handle to avoid encoding internal malloc(9) data structures in
- * modules, which will statically allocate struct malloc_type.
+ * Public data structure describing a malloc type.
  */
 struct malloc_type {
 	struct malloc_type *ks_next;	/* Next in global chain. */
-	u_long		 ks_magic;	/* Detect programmer error. */
+	u_long		 ks_version;	/* Detect programmer error. */
 	const char	*ks_shortdesc;	/* Printable type name. */
-	void		*ks_handle;	/* Priv. data, was lo_class. */
+	struct malloc_type_internal ks_mti;
 };
 
 /*
@@ -141,7 +140,12 @@
 #ifdef _KERNEL
 #define	MALLOC_DEFINE(type, shortdesc, longdesc)			\
 	struct malloc_type type[1] = {					\
-		{ NULL, M_MAGIC, shortdesc, NULL }			\
+		{							\
+			.ks_next = NULL,				\
+			.ks_version = M_VERSION,			\
+			.ks_shortdesc = shortdesc,			\
+			.ks_mti = { 0 },				\
+		}							\
 	};								\
 	SYSINIT(type##_init, SI_SUB_KMEM, SI_ORDER_THIRD, malloc_init,	\
 	    type);							\
Index: head/sys/sys/param.h
===================================================================
--- head/sys/sys/param.h
+++ head/sys/sys/param.h
@@ -60,7 +60,7 @@
  *		in the range 5 to 9.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 1300126	/* Master, propagated to newvers */
+#define __FreeBSD_version 1300127	/* Master, propagated to newvers */
 
 /*
  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,